英会話レッスン楽しかったです。 を英語に訳すと？

I really enjoyed your lesson.
や
Thank you for a fun lesson.
と言えば
楽しんだ気持ちが伝わりますよ。

状況によって伝えたいことの細部が異なるかもしれないので、いくつか書いてみました。

The English lesson was very interesting. I enjoyed it very much.

Your lesson of English conversation was so enjoyable. I had a very good time.

I really enjoyed the lesson of English conversation the other day.